Are you already familiar with the diagnostic manual for mental disorders, titled: 'DSM IV: Diagnostic and Statistical Manual for Diagnosing Mental Disorders'.

Interestingly, in various sections of this 'authority' (the guidelines are used by health professionals in all regions of the world)... clear references are described which illustrate how certain 'hand behaviors' (gestures & expressions) can signal severe mental conditions- & problems.

Some of the examples related to hands that are mentioned in the DSM IV are:

In the section 'Hand Motorics' of my new website I describe various topics & examples which can play a significant role in the assessment of certain THEMES (diseases & psychological disorders) via the hand, see: